Augmenting Visual Search Performance With Transcranial Direct Current Stimulation (tDCS)

Military personnel endure rigorous and demanding man-hours designated to monitoring and locating targets in tasks such as cyber defense and Unmanned Aerial Vehicle (UAV) operators. These tasks are monotonous and repetitive, which can result in vigilance decrement. The objective of the study was to implement a form of noninvasive brain stimulation known as transcranial DC stimulation (tDCS) over the left frontal eye field (LFEF) region of the scalp to improve cognitive performance. The participants received anodal and cathodal stimulation of 2 mA for 30 min as well as placebo stimulation on 3 separate days while performing the task. The findings suggest that anodal and cathodal stimulation significantly improves detection accuracy. Also, a correlation was detected between percent of eye closure (PERCLOS) and blinking frequency in relation to stimulation condition. Our data suggest that tDCS over the LFEF would be a beneficial countermeasure to mitigate the vigilance decrement and improve visual search performance.     

经颅直流电刺激在抑郁症治疗中的应用

已有的神经影像学研究成果揭示, 抑郁症发作的重要原因之一是大脑前额叶皮层结构和功能受损。经颅直流电刺激(tDCS)作为一种无创脑刺激, 选取前额叶皮层作为刺激区域, 通过调节皮层兴奋性来治疗抑郁症, 能够有效缓解抑郁症状和改善受损的认知功能, 疗效明显且持久稳定。针对tDCS在抑郁症治疗研究中的问题, 未来可从有效性、个体差异以及预防干预等六个方面进一步研究, 以期tDCS作为一种具有潜力的治疗手段, 在临床上有更为广泛地应用。     

Stimulating Creativity: Modulation of Convergent and Divergent Thinking by Transcranial Direct Current Stimulation (tDCS)

Creativity has been conceptualized as involving 2 distinct components; divergent thinking, the search for multiple solutions to a single problem, and convergent thinking, the quest for a single solution either through an analytical process or the experience of insight. Studies have demonstrated that these abilities can be improved by cognitive stimulation, mood, and meditation. This investigation examined whether convergent and divergent thinking can be enhanced by noninvasive transcranial direct current stimulation (tDCS). In different sessions, participants received bilateral stimulation over the dorsolateral prefrontal cortex—DLPFC (Experiment1) and over the posterior parietal cortex–PPC (Experiment2), while performing the Compound Remote Associative task (CRA) assessing convergent thinking and the Alternative Uses Task (AUT) assessing divergent thinking. In Experiment1, anodal-left cathodal-right stimulation over the DLPFC significantly enhanced CRA performance. In Experiment2, stimulations over the PPC significantly increased insight solutions and decreased analytical solutions compared to the no stimulation condition. These findings provide direct evidence for the role of the left DLPFC in convergent and divergent thinking and a mediating role of the PPC in problem-solving behavior, presumably through attentional processes. From a methodological perspective, brain stimulation can be used as a tool to modulate and to explore components of creativity.     

经颅直流电刺激右侧颞顶联合区对道德意图加工的影响*

对行为意图的理解是人类进行道德判断的重要依据,大量研究表明,右侧颞顶联合区是意图加工的关键脑区。为考察该脑区在道德判断中的重要作用,采用经颅直流电刺激技术阳极刺激右侧颞顶联合区,探讨促进该脑区的活动对被试在道德判断中意图及相关信息加工的影响。结果发现与假刺激条件相比,阳极刺激后道德判断反应时显著延长,在伤人未遂和意外伤人条件下差异显著,证明促进右侧颞顶联合区的激活能影响道德判断中的意图加工,尤其在意图与结果产生冲突的条件下效应更加显著。     

Cognitive Offloading: Structuring the Environment to Improve Children's Working Memory Task Performance

Research has shown that adults can engage in cognitive offloading, whereby internal processes are offloaded onto the environment to help task performance. Here, we investigate an application of this approach with children, in particular children with poor working memory. Participants were required to remember and recall sequences of colors by placing colored blocks in the correct serial order. In one condition the blocks were arranged to facilitate cognitive offloading (i.e., grouped by color), whereas in the other condition they were arranged randomly. Across two experiments (total N = 166) the ordered condition improved task performance for children with low working memory ability. In addition, participants in Experiment 2 rated the difficulty of the two arrangements and performed a further condition in which they were given an opportunity to freely arrange the blocks before completing the task. Despite performing better in the ordered condition, children with low working memory ability did not rate the ordered arrangement as easier, nor did they choose an ordered arrangement when given the opportunity to do so. This research shows that cognitive offloading can also be a useful process in populations other than typical adults, and the implications of this work for supporting children with poor working memory are discussed.     

The Role of Switching,Inhibition and Working Memory in Older Adults' Performance in the Wisconsin Card Sorting Test

ABSTRACT

The Wisconsin Card Sorting Test (WCST) is considered a typical executive test. However, several interesting questions are still open as to the specific executive processes underlying this task. In the present study, we explored how local and global switching, inhibition and working memory, assessed through the Number–Letter, the Stop Signal and the Reading Span tasks, relate to older adults' performance in the WCST. Results showed that older adults' performance variability in the number of perseverative errors was predicted by the local switch component of the Number–Letter task. Results also showed age-related differences in inhibition, working memory and global switching, while local switching resulted largely spared in aging. This study provides evidence that switching abilities may contribute to performance of older adults in the WCST. It also provides initial evidence suggesting that switching processes, associated with local switch costs, are involved in performance on the WCST, at least in older adults.     

Working Memory Deficits in Boys with Attention-deficit/Hyperactivity Disorder (ADHD): The Contribution of Central Executive and Subsystem Processes

The current study investigated contradictory findings from recent experimental and meta-analytic studies concerning working memory deficits in ADHD. Working memory refers to the cognitive ability to temporarily store and mentally manipulate limited amounts of information for use in guiding behavior. Phonological (verbal) and visuospatial (nonverbal) working memory were assessed across four memory load conditions in 23 boys (12 ADHD, 11 typically developing) using tasks based on Baddeley's (Working memory, thought, and action, Oxford University Press, New York, 2007) working memory model. The model posits separate phonological and visuospatial storage and rehearsal components that are controlled by a single attentional controller (CE: central executive). A latent variable approach was used to partial task performance related to three variables of interest: phonological buffer/rehearsal loop, visuospatial buffer/rehearsal loop, and the CE attentional controller. ADHD-related working memory deficits were apparent across all three cognitive systems--with the largest magnitude of deficits apparent in the CE--even after controlling for reading speed, nonverbal visual encoding, age, IQ, and SES.     

“热”执行对注意缺陷多动障碍和阅读障碍儿童言语工作记忆的影响

ADHD儿童在与背外侧前额叶(DLPFC)相关的"冷"执行功能上的缺陷已大量证实,但在与眼眶和中前额叶皮层(OMPFC)相关的"热"执行功能上,ADHD儿童是否存在缺陷则未可知。与儿童赌博任务实验范式(该任务中"热"启动对"冷"执行起到抑制作用)不同,本研究考察趣味言语N-back任务是否对ADHD和阅读障碍儿童的成绩有促进作用。枯燥N-back任务考察的是言语工作记忆的纯认知特征,而趣味任务则卷入了"热"执行对"冷"执行的影响。结果表明,在枯燥任务上,ADHD和阅读障碍儿童的成绩均明显低于正常儿童,二者之间差异不显著,在趣味任务成绩上,ADHD儿童与正常儿童的成绩没有显著差异,而阅读障碍儿童成绩落后于正常控制组和ADHD组,在成绩变化的趋势上,ADHD儿童在趣味任务上成绩明显提高,而阅读障碍儿童则无明显改善。结果说明ADHD和阅读障碍儿童的言语工作记忆均存在明显的缺陷,但是机制不同,"热"执行对提高ADHD的言语工作记忆有明显的促进作用,ADHD的"冷"执行缺陷能够通过"热"执行的调节得到改善。     

前摄抑制对儿童注意缺陷多动障碍(ADHD)和阅读障碍的言语工作记忆的影响

ADHD和阅读障碍儿童在言语工作记忆上的缺陷得到了大量研究的证实,但是二者机制并不相同,前摄抑制对工作记忆容量产生了不利的影响,主要影响的也是中央执行功能。研究将最近探测任务和n-back任务相结合,直接比较被试在最近负探测和非最近负探测条件下记忆成绩的差异,以考察前摄抑制对两种障碍言语工作记忆的影响,被试是60名障碍儿童(阅读障碍和ADHD)和17名正常儿童,年龄均在7至12岁之间。结果发现,受前摄抑制的影响,正常被试和障碍被试成绩均明显下降,具体而言,ADHD和ADHD伴随阅读障碍组成绩大幅下滑(26.44%,28.44%),程度明显高于正常儿童和阅读障碍儿童(14.62%,15.84%),后两者差异并不明显,这说明前摄抑制是影响工作记忆容量的重要因素,并且ADHD儿童更加容易受到前摄抑制的影响,这是导致其工作记忆成绩缺损的重要原因,而阅读障碍儿童能够像正常儿童一样,在一定程度上处理前摄抑制,ADHD和阅读障碍组在言语工作记忆缺损机制上存在差异。